The SBC Session Border Controller provisions basic geo-redundancy and DNS load balancing.
Background Information
The Integrated Access Device (IAD) is registered with an Application Server (AS).
The AS is protected by an SBC. The IAD discovers the SBC via DNS resolution and the SBC discovers the AS by pre-configured routing or external DB dip (e.g. ENUM).
Once registered, the IAD communicates with a specific SBC, and the SBC forwards requests to the specific AS (address was stored during registration).
For calls terminating to the IAD, the IADs register their AORs.
IAD has been registered by two paths and can afford for one path to fail and still receive service on the other, when it supports outbound. In a normal scenario where the IAD registers through one path and is unable to refresh the register, it moves on to an alternate SBC from DNS.
Description
Basic Service Availability- DNS
The IAD is configured with a FQDN identifying a set of SBCs.
The DNS supplies multiple SBC IP addresses (local, remote or a combination of both).
Basic geo-redundancy and load balancing between the SBCs are enabled. With geo-redundancy, if an SBC fails, the IAD re-registers through a different path.